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smoke from valve cover pcv thing


lynchfourtwenty

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Blow by. Gasses are squeezing past worn compression rings that aren't up to doing their job. A compression test is good but a leak down test is better for showing the % of leakage. Up to 25% loss isn't considered too bad. Sounds bad is all.

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You wouldn't use it much, and you would need a compressor to use it if you did have it.

 

The compression tester only reads the peak pressure reached. The leak down test shows how much or how fast it leaks out past rings valves or head gasket.

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Do this test: open the driver's door, and stand where you can kinda see the back of the truck or exhaust pipe. Rap on the throttle real fast (rev it to 4000 rpm or so, but immediately let off). Do this three times.

 

* If you see any slightly-bluish smoke coming from the back of the truck, that's another sign the rings are shot. This bluish-white smoke doesn't evaporate it just blows away in the wind.

* White smoke that disappates is normal.

* Black smoke means carb or ignition problems.

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When I was in the car buying business, that's how we tested to see if a car engine was good:

1. Pull PCV hose, look for faint smoke

2. Rap throttle, looks for smoke

If you cannot see any smoke, the rings are good.

The test has never failed. Some engines at 150,000 miles are still good. Most at 100,000 miles are still good. A few at 30,000 already have a problem :-)

 

 

But even so, marginal valve guides & seals can still cause smoke when first starting the engine. It doesn't test for that. That's something you normally only see after letting the car sit a while, then starting it. EDIT: as datsunmike just said. Yep.

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last time i did a compression test (not even a years worth of driving ago) but literally like 2 years ago.. anyways last time i did it i think it was like 160 or so accross all cyls, could it have anything to do with sitting alot lately not bein drivin.. cause when i drove her daily it didnt do any of this.. BUT i do ride her hard.. high rpms alot.. but shes always got oil, always has good oil pressure and never over heats... could my exhaust bein broken only a few inches after the header have anything to do with this?? i mean its like snapped completely an the pipe is hangin lol

 

lol i posted after you but ya she has been sittin awhile..

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High RPMs and full throttle are exactly what wear out rings. Aside from old oil... I once wore out a nice Datsun engine in 12 months with high RPM (6000 rpm) blasts on every shift. That's why a big engine is nice, you don't have to wring its neck to get high performance...

 

On the other hand, a Datsun engine crusing at 4000 or even 4500 rpm will last for years.

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yea, im pretty damn mean to her.. lol no biggy i wont kill her completely, and like i said i think im going to keep my eyes peeled for a free or cheap l20 thats it working or close to working condition so i can easily tear it apart an replace some shit, prolly do some rod bearings crank bearings piston rings an what not, my timing chain is like new sorta.. so i will reuse it.. i will also prolly use a ka oil pump, i will also re do the valve seals in my a87 head an the seats an guides, maybe some new valves too if needed .. im not looking to spend much or get any additional power, just something i can rely on an abuse alot

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yea, damnit!! lol well i will take it easy on her i guess.. since my car isnt in driving condition right now, i really wish i had a garage to work on my car in.. so i could just swap engines an shit an be good to go.. i got the engine already just no where to work on the car :( i think she has 1 last drive in her so im saving it lol

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thats what im runnin now, its so fuckin cold out it takes forever to warm up, even the other day i had been drivin around an shit an the only time the needle move was when i got on it gettin on sr500 other then that it ran at like 150 or 160 or something barely past where the guage starts, even in burgerville drive through it didnt warm up for shit, maybe cause i had the heater on i dont know.. lol but i'll give it a try for sure man

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thats what im runnin now, its so fuckin cold out it takes forever to warm up, even the other day i had been drivin around an shit an the only time the needle move was when i got on it gettin on sr500 other then that it ran at like 150 or 160 or something barely past where the guage starts, even in burgerville drive through it didnt warm up for shit, maybe cause i had the heater on i dont know.. lol but i'll give it a try for sure man

 

If thats all the warmer the motor is getting, then you have a thermostat problem. This cold weather will still allow the motor to warm up and produce hot water for your heater.

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